Ultra Tuning: Decoding the Torque Tab's SPD Table

[Imagineaudio]

So, I went through all of these programming threads a few months ago. Smorgasbord, you've done a tremendous amount of work here and it's amazing you took the time to write all of this up. I'm revisiting as I'm programming another bike and looking for a different feel than the first one. This second one is primarily for road riding vs the other that is just for trail riding. I'm having trouble trying to find settings that allow me to pedal with a good amount of resistance at speeds of 16-19mph that doesn't have me at the top of the torque output. In other words, I'm looking for more headroom above so that pedaling harder returns more motor output. Currently, I find that when I'm at a comfortable cadence, pedaling any harder is just adding manual effort on top of the motor and the torque mapping is already topped out.

How would you recommend approaching the settings with this goal? I would need the torque sensing to be less sensitive at a certain cadence, but still need it to respond to a sharp increase in pressure to give more boost, I feel like this would feel more natural. Currently, I'm finding that the comfortable cadence/pedal pressure is at the top of the range.

 

[smorgasbord]

My first thought is to look at your settings for the Voltage Section of the Torque Tab. That's where the mapping from the torque you apply to the pedal gets mapped to the torque value that gets input into the SPD table. It's a bit convoluted, but my understanding is that:

1) There's a torque sensor in the Ultra motor, measuring applied torque and outputting a voltage. The Voltage Table converts that voltage to a Kg, which is input to the SPD Table. So, you have actual applied force to voltage via the torque sensor, and then voltage back to force via the Voltage table. And then SPD Table to convert force to amps.
2) That torque sensor outputs some voltage even when no pressure is being applied to the pedals. Set your Base Voltage to 1 or 2 mV above that. If you can't measure that per the instructions at the link, just enter 760.
3) The torque sensor maxes out at about 3255mV.
4) Now the thing is to set the table values so that you get the torque to power curve you're looking for.
5) Values, including the Base Voltage should add up to 3255 or so.

Since you want more output at harder pedal pressures, you'll not want as aggressive a curve as some my suggestions here, assuming you're physically capable of putting 60kg of force while you pedal (I can and I'm not an especially strong rider, but if you're light in weight that might be hard for you).

Look at the post I linked for the spreadsheet and try some different percentages there, or create your own mapping.

Let us know how it goes!